Difference between revisions of "Team:UESTC-China/Description"

As we know, Antibiotics are widely applied to the treatment and prevention of diseases for humans and animals, saving countless lives. It is estimated that antibiotic consumption worldwide to lie between 100,000 and 200,000 tons per year[1]. The abuse of antibiotics has caused serious environmental pollution. For example, in 2013, China consumed 92,700 tons of antibiotics, 54,000 of them were excreted, among the 54000 tons, most (99.6％) are released into the environment[2], posing a huge threat to people and ecosystems.

Antibiotics have the most serious impact on the water environment, because most of them eventually enter the water environment. The 2019 Science cover article conducted a large-scale survey of rivers in 72 countries, and 66% of the 711 sampling sites found antibiotics [3]. Besides, In the literature, we found examples of considerable antibiotic pollution in fresh waters. In the Americas, antibiotic concentrations of up to 15 μg/L have been measured; with higher concentrations reported from European and African studies (over 10 μg/L and 50 μg/L respectively), and in Asian-Pacific countries concentrations over 450 μg/L have been detected[1].

Some antibiotics in water could affect microorganisms at concentrations below 10 ug/L[1], inducing Anti-Microbial Resistance (AMR). Bacteria with AMR could resist the action of the drug, and through the biological chain, it may cause potential harm to other living creatures and human. According to the report, Current worldwide deaths attributable to AMR, including antimalarial and antiviral resistance, have been estimated at ~700,000 per year, rising to 10 million per year by 2050 if present trends continue[4,5].

So we started thinking, could we do something to help solve antibiotic pollution?

First, we want to figure out where the antibiotics come from. Actually, we found that antibiotics are everywhere in our life. Rivers, soil and even air[6], they all exist. In order to know the sources of antibiotics in the environment, we visited the no. 4 water purification plant in Chengdu and learned that the antibiotics in sewage mainly comes from two kinds of emissions. One is in production, such as pharmaceutical wastewater, the other is in use, mainly medicine antibiotics and veterinary antibiotics, among which medical antibiotics and veterinary antibiotics are the main ones.

Most antibiotics end up in water, but most conventional treatments applied in wastewater treatment plants and drinking water treatment plants (such as coagulation, flocculation, sedimentation and filtration) were unsuccessful in the removal of these compounds, because of which there developing some approaches to treat antibiotics in water. Here we list three important approaches in table 1[7].

We note that studies have shown that improper disposal of unused/expired drugs, which are directly discharged in the sewage network or deposited in landfills, can also be considered as significant points of antibiotic contamination[8,9]. However, our investigation shows that people pay little attention to expired drugs.

The Chinese family expired drugs recycling white paper made clear that China has an estimated 78.6% of households have small family medicine, among them, 30% to 40% of the drug than valid for more than 3 years, more than 80% of households have no the habit of his regular cleaning kit, the expired drugs produce family of about 15000 tons a year[10,11]. According to the survey, the most common categories of family medicines are cough and cold medicines (47.8%) and systemic antibiotics (30.0%)[12]. Many of these two kinds of medicines contain antibiotic components. Therefore, we believe that the disposal of expired medicines can improve the pollution of antibiotics to some extent.

In our project, we take CIP for example to build a system of degrading antibiotics with synthetic biology.

Ciprofloxacin is a commonly used antibiotic in clinical practice, which is a class of quinolone antibiotics, and it has been shown that ciprofloxacin and erythromycin have the highest rates of resistance (20% to 60%) among the antimicrobial agents considered essential to human medicine[13]. A large-scale survey of rivers in several countries and regions around the world found that among the samples of rivers with the highest levels of antibiotics, the commonly prescribed drug ciprofloxacin was eight times over the safe level[3]. Of all antibiotics, ciprofloxacin is one of the most widely used and harmful.

We noticed that the enzyme CrpP found in 2018 has the ability to phosphorylate and thus degrading CIP[14], so we utilized CrpP CDS as a basis of CIP biodegradation pathway. Meanwhile, we added a quorum sensing system to enhance the expression of CrpP by E.coli[15]. When upstream inducible promoter is activated by CIP, quorum sensing system will facilitate downstream CrpP’s expression and degrade CIP consequently.

Compared with other present CIP treatment methods, our biodegradation system has following advantages.

1. Low energy consumption.
2. Final product has certain value.
3. It’s simpler than other treatment methods.

The whole system can be widely used in all kinds of antibiotics if you switch to genes that express proteins degrading different antibiotics.

The entire system was introduced into a specific processing device——drug avenger. Our systems and device has been verified in the field of expired drug recycling, and by changing some elements, it can handle antibiotics pollution in other fields.

Besides, through the modeling we solved the problem of the layout of the device, and anyone can use our model to place the devices in any community by changing the parameters.

[1]Danner, M. C., Robertson, A., Behrends, V., & Reiss, J. (2019). Antibiotic pollution in surface fresh waters: Occurrence and effects. Sci. Total Environ., 664, 793-804.
[2] Zhang, Q. Q., Ying, G. G., Pan, C. G., Liu, Y. S., & Zhao, J. L. (2015). Comprehensive evaluation of antibiotics emission and fate in the river basins of China: source analysis, multimedia modeling, and linkage to bacterial resistance. Environ. Sci. Technol., 49(11), 6772-6782. [3]https://www.sciencenews.org/article/world-rivers-dangerous-levels-antibiotics
[4] Roope, L. S. J., Smith, R. D., Pouwels, K. B., Buchanan, J., Abel, L., Eibich, P., . . . Wordsworth, S. (2019). The challenge of antimicrobial resistance: What economics can contribute. Science, 364(6435), eaau4679.
[5] Willyard, C. (2017). The drug-resistant bacteria that pose the greatest health threats. Nature, 543(7643), 15.
[6]Wang bin, zhou ying, & jiang qingwu. (2014). Environmental antibiotic pollution and its impact on human health. Chinese journal of preventive medicine, 48(6), 540-544.
[7] Homem, V., & Santos, L. (2011). Degradation and removal methods of antibiotics from aqueous matrices – A review. Journal of Environmental Management, 92(10), 2304-2347.
[8] Kumar, M., Jaiswal, S., Sodhi, K. K., Shree, P., Singh, D. K., Agrawal, P. K., & Shukla, P. (2019). Antibiotics bioremediation: Perspectives on its ecotoxicity and resistance. Environment International, 124, 448-461.
[9] Akici, A., Aydin, V., & Kiroglu, A. (2018). Assessment of the association between drug disposal practices and drug use and storage behaviors. Saudi Pharmaceutical Journal, 26(1), 7-13.
[10]http://health.people.com.cn/n1/2019/0815/c1473931297021.html
[11]http://www.xinhuanet.com/health/201803/13/c_1122532216.html
[12] Dong Haiyan. (2014). Eight adults did not clean the medicine box in time. Health Guide, 20(1), 62-62.
[13] Van Boeckel, T. P., Pires, J., Silvester, R., Zhao, C., Song, J., Criscuolo, N. G., ... & Laxminarayan, R. (2019). Global trends in antimicrobial resistance in animals in low-and middle-income countries. Science, 365(6459), eaaw1944.
[14] Chávez-Jacobo, V. M., Hernández-Ramírez, K. C., Romo-Rodríguez, P., Pérez-Gallardo, R. V., Campos-García, J., Gutiérrez-Corona, J. F., . . . Ramírez-Díaz, M. I. (2018). CrpP Is a Novel Ciprofloxacin-Modifying Enzyme Encoded by the Pseudomonas aeruginosa pUM505 Plasmid. Antimicrobial agents and chemotherapy, 62(6), e02629-02617.
[15] http://parts.igem.org/Lux?tdsourcetag=s_pctim_aiomsg